Device for introducing rods, dowels or the like into concrete paved carriageways

ABSTRACT

A device for introducing rods, dowels or the like into unreinforced concrete paving so that the rods or dowels extend across joints in the resultant concrete slabs to act as loadtransfer dowels, and/or tie bars to prevent the joints opening out, such device comprising a holder positioned in front of the usual conforming plate of a concrete paving machine, one or more guide tubes connected to the holder, and trigger means for timing the release of rods or dowels located by the holder to pass through the or each tube for positioning in the wet concrete.

United States Patent [191 Cochrane et al.

[ 1 Nov. 19, 1974 DEVICE FOR INTRODUCING RODS,

DOWELS OR THE LIKE INTO CONCRETE PAVED CARRIAGEWAYS [75] Inventors: Kenneth Alfred Cocbrane, Matlock;

Robert Geofrey Holloway, Chesterfield, both of England [73] Assignee: Robert McGregor & Sons Limited,

Derbyshire, England 22 Filed: Nov. 13, 1972 21 App]. No.: 305,897

[30] Foreign Application Priority Data Dec. 23, 1971 Great Britain 59854/71 [52] US. Cl. 404/100 [51] Int. Cl. E01c 11/18 [58] Field of Search 404/100, 108, 88, 102, 404/105, 98

[56] References Cited UNITED STATES PATENTS 286,861 10/1883 Speed 404/105 X 1,996,153 4/1935 Heltzel 404/87 2,225,015 12/1940 Lebelle 404/98 X 2,544,113 3/1951 Snead 404/108 3,083,621 4/1963 Woolley 404/100 3,261,272 7/1966 Jennings 404/98 3,274,906 9/1966 Worson 404/87 3,443,495 5/1969 Heltzel 404/100 3,749,505 7/1973 Miller 404/98 Primary Examiner-Nile C. Byers, Jr. Attorney, Agent, or Firm-Norris & Bateman [5 7] ABSTRACT plate of a concrete paving machine, one or more guide tubes connected to the holder, and trigger means for timing the release of rods or dowels located by the holder to pass through the or each tube for positioning in the wet concrete.

11 Claims, 4 Drawing Figures PATENTEL, W 1 9 I914 3,8491) 1 e SHEET 10F 3 PATENTL 513V 1 91974 3,849,016

SHEET 2 BF 3 DEVICEFOR INTRODUCING RODS, DOWELS OR THE LIKE INTO CONCRETE PAVED CARRIAGEWAYS This invention relates to a device for introducing rods, dowels or the like into concrete paved carriageways. More particularly, the invention relates to such a device for inserting rods or dowels into unreinforced concrete paving so as to extend across the joints in the resultant slabs, thereby acting as load-transfer dowels, and/or tie bars to prevent the joints opening out. Normally the paving is laid in a continuous length and provision is made so that the paving cracks at predetermined places, the cracks being bridged by the rods or dowels. The cracks can be induced, for example, by notching the concrete surface at the desired location.

Hitherto, the introduction of rods into concrete paved carriage ways has generally been effected by fixing the rods to the sub-base of the carriageway ahead of the paving apparatus. This operation has been carried out in a number of different ways, all of which are laborious and expensive and usually entail some preparatory work to the sub-base. As the rods need to be positioned some distance ahead of the paving apparatus, their supporting assemblies are susceptible to accidental displacement or damage, and can even be damaged before positioning. Such supporting assemblies tend to be fairly complex and only have the sole function of locating the rods or dowels in position until they are encased in concrete.

It is an aim of the invention to provide a device for introducing rods, dowels or the like into paved carriageways wherein the rods or dowels are punched through the surface of the wet concrete. This device substantially eliminates the disadvantages encountered when the rods or dowels are mounted on the sub-base.

With this aim in view, the invention provides a device for introducing rods, dowels or the like into concrete paved carriageways, such device comprising a holder positioned in front of the conforming plate of a concrete paving machine, one or more guide tubes connected to the holder, and trigger means for timing the release of rods or dowels located by the holder to pass through the or each guide tube for positioning in the wet concrete.

The invention will be described further, by wayof example, with reference to the accompanying drawings,-

and FIGS. 3 and 4 are enlarged diagrammatic crosssections showing the feeding of therods or dowels.

The drawings show a device for introducing rods, dowels or the like into wet concrete paved carriageways, the device comprising a holder in the form of a beam 10 positioned on a concrete paving machine in front of a conforming plate 11 of the concrete paving machine. A plurality of guide tubes 12 are connected to the beam 10 which houses trigger means 13 for timing the release of rods or dowels 14 which pass along the guide tubes 12 into the web concrete 15.

Each guide tube 12 comprises a respective circularsectioned first part 16 which is approximately the length of the rods or dowels 14 and which tapers and merges with a respective reduced diameter second part 17. At the free end of each second part 17, a respective upper portion of the tube is removed to form steps 18.

The trigger means 13 comprises a movable crosshead 19 upon which are mounted a plurality of pusher fingers 20, one finger 20 being provided for each guide tube 12 so as to engage the lowermost rod or dowel 14 of a stack of dowels located in a respective magazine 21. Dowels or rods 14 may be fed by hand into each magazine 21 through respective flared tubes 22.

The usual pre vibrators 23, 24 operated by means not shown, are provided to improve the consistency of the I concrete passing beneath the conforming plate 11.

The trigger means 13 may be actuated manually or automatically so as to ensure that the rods or dowels 14 are positioned as desired. FIG. 3 shows the trigger means 13 at the ready position wherein the crosshead 19 is ready to commence pushing the lowermost rods or dowels, via the fingers 20, into the guide tubes 12. FIG. 4 illustrates the dowel insertion stroke, wherein three dowels 14 are required in the: tubes 12 to push the dowel 14 nearest the open end of the tubes into the wet concrete.

The crosshead 19 moves rearwards relative to the concrete paving machine at the same speed as the machine moves relative to the ground; that is, the rods or dowels 14 being inserted into the wet concrete are stationary relative to the ground. When the crosshead 19 has reached the limit of its travel, it automatically returns to its position as shown in FIG. 3, the fingers 20 being spring-loaded to clear the rods or dowels 14 30 the return stroke.

The first parts 16 of the guide tube 12 are approximately one and a half inches inside diameter, whilst the second parts 17 are approximately one and an eighth inches inside diameter. It has been found in practice that rods or dowels can be fed along guide tubes as shown in the drawings more easily than along tubes of constant diameter. The guide tubes 12 are positioned to lay rods or dowels 14 at a lateral spacing of about l2 inches (approximately 300 mm) across the width of a concrete carriageway and joints are wet formed, for example, by notching the surface of the concrete, so that the joints extend through the rods or dowels 14.

The length of the guide tubes 12 is arranged so that the tubes protrude into the web concrete beneath the conforming plate 11 and terminate at a position where the concrete is sufficiently mobile to ensure that no unintentional voids are formed, but not so mobile as to produce any appreciable displacements of the rods or dowels 14 in the vertical or horizontal directions. To reduce the criticality of the termination points of the guide tubes 12, the ends of the tubes are stepped as shown at 18.

The trigger means 13 can be operated mechanically, electrically, hydraulically or pneumatically or can use any combination of these power systems so that the rods or dowels 14 are ejected into the wet concrete at a rate proportional to the forward ground speed of the paving machine.

It will be appreciated from the foregoing example that the invention provides a simple, easy to manufacture and easy to operatedevice for inserting accurately positioned rods or dowels into wet concrete pavement, and in particular slip-formed pavement, without the use of any form of ancillary supports for the rods or dowels.

The invention is not limited to the precise details of 5 the foregoing example, and variations may be made thereto. For example, the trigger means 13 may be other than that shown and the guide tubes 12 may have a constant diameter along their length. Also, the steps 18 can be of any desired shape and size.

We claim:

1. A device for introducing rods, dowels or the like into concrete paved carriageways, such device comprising a holder positioned in front of the conforming plate of a concrete paving machine, magazine means providing a supply of rods or dowels within said holder, a guide tube connected to the holder, in position to longitudinally receive rods or dowels from said magazine means, and means for extracting rods or dowels from said magazine in the holder and moving them endwise into and through said guide tube for positioning in the wet concrete.

2. A device as defined in claim 1, wherein a plurality of magazines are provided in said holder with a guide tube and operatively related extracting means associated with each magazine.

3. A device as claimed in claim 2, wherein the holder is in the form of a beam extending transversely of the paving machine.

4. A device as claimed in claim 2, wherein said extracting means comprises a movable crosshead upon which are mounted a plurality of spring-loaded pusher fingers, one finger being provided for each guide tube so as to engage the lowermost rod or dowel of a stack of dowels located in a respective magazine and move it into the guide tube.

5. A device as claimed in claim 4, wherein a respective flared tube is provided for feeding rods or dowels into each magazine.

6. A device as claimed in claim 2 wherein the lengths of said guide tubes are such that they project into the wet concrete beneath said conforming plate.

7. A device as claimed in claim 1, wherein said guide tube comprises a respective first partwhich tapers and merges with a respective second part of reduced crosssection.

8. A device as claimed in claim 7, wherein at the free end of each second part of the guide tube, a respective upper portion of the tube is removed to form a step.

9. A device as claimed in claim 1, wherein previbrators are provided in front of the conforming plate to improve the consistency of the wet concrete passing under the plate.

10. A device as claimed in claim 1, wherein the length of said guide tube is such that the tube protrudes into the wet concrete beneath the conforming plate and terminates at a position where the concrete is sufficiently mobile to ensure that no unintentional voids are formed, but not so mobile as to produce any appreciable displacements of the rods imbedded or dowels in the vertical or horizontal directions.

11. A device as claimed in claim 1, wherein said extracting means is so operated that rods or dowels are ejected in the wet concrete at a rate proportional to the forward ground speed of the paving machine. 

1. A device for introducing rods, dowels or the like into concrete paved carriageways, such device comprising a holder positioned in front of the conforming plate of a concrete paving machine, magazine means providing a supply of rods or dowels within said holder, a guide tube connected to the holder, in position to longitudinally receive rods or dowels from said magazine means, and means for extracting rods or dowels from said magazine in the holder and moving them endwise into and through said guide tube for positioning in the wet concrete.
 2. A device as defined in claim 1, wherein a plurality of magazines are provided in said holder with a guide tube and operatively related extracting means associated with each magazine.
 3. A device as claimed in claim 2, wherein the holder is in the form of a beam extending transversely of the paving machine.
 4. A device as claimed in claim 2, wherein said extracting means comprises a movable crosshead upon which are mounted a plurality of spring-loaded pusher fingers, one finger being provided for each guide tube so as to engage the lowermost rod or dowel of a stack of dowels located in a respective magazine and move it into the guide tube.
 5. A device as claimed in claim 4, wherein a respective flared tube is provided for feeding rods or dowels into each magazine.
 6. A device as claimed in claim 2 wherein the lengths of said guide tubes are such that they project into the wet concrete beneath said conforming plate.
 7. A device as claimed in claim 1, wherein said guide tube comprises a respective first part which tapers and merges with a respective second part of reduced cross-section.
 8. A device as claimed in claim 7, wherein at the free end of each second part of the guide tube, a respective upper portion of the tube is removed to form a step.
 9. A device as claimed in claim 1, wherein pre-vibrators are provided in front of the conforming plate to improve the consistency of the wet concrete passing under the plate.
 10. A device as claimed in claim 1, wherein the length of said guide tube is such that the tube protrudes into the wet concrete beneath the conforming plate and terminates at a position where the concrete is sufficiently mobile to ensure that no unintentional voids are formed, but not so mobile as to produce any appreciable displacements of the rods imbedded or dowels in the vertical or horizontal directions.
 11. A device as claimed in claim 1, wherein said extracting means is so operated that rods or dowels are ejected in the wet concrete at a rate proportional to the forward ground speed of the paving machine. 